PCI or PCIe? They are different, so make sure you get the right thing.
PCIe thunderbolt cards can be found on aliexpress for $70-100 AUD.
I have this one:
https://a.aliexpress.com/_mLsmPzv
You need to have a thunderbolt port (not the same thing as USB, check your device specs), and you need a power supply, I use an old PC power supply.